Bats may fit in perfectly with the haunted souls rumored to wander the walkways of historic Fort Delaware, but there are far fewer of these flying mammals than there once were. Of the handful of little brown bat colonies tracked by the state, all were lost to white-nose syndrome, Niederriter said.

White-nose syndrome is caused by a fungus that grows in cold, dark and damp places – exactly where bats like to nest – such as Fort Delaware. After infecting hibernating bats, the fungus looks like a white, fuzzy frosting on bats’ faces and can cause them to go a little bonkers, like flying outside in the daytime during winter, according to the White-Nose Syndrome Response Team website.

Because of the fungus, visitors are now asked to wear foot coverings during their visit to the secluded historical site, where educational signs about the crisis also let people know that those little creepy critters need help. Those efforts to decrease the spreading of the fungus and increase public awareness were supported by a $15,785 grant from the U.S. Fish & Wildlife Service awarded earlier this year.

7 things about bats you may not know

1. Eight species of bats are known to live in First State leaf piles, attics, barns and historical forts (Delaware doesn’t really have any caves). Those species include big brown bats, little brown bats, tri-colored bats, northern long-eared bats, eastern red bats, hoary bats, silver-haired bats and evening bats. It is possible there may be some eastern small-footed bats flitting around, too.

2. Big brown bats are the most commonly spotted species in Delaware, although that title historically belonged to little brown bats before they were hit by white-nose syndrome.

3. A little brown bat can eat its weight in insects every night. That would be like a person eating 100 Big Macs in one day.

4. Some studies estimate that bats save farmers more than $3 billion in pesticides because they eat so many pesky bugs.

5. At least nine species of North American bats – which include five known to frequent Delaware – have been hard-hit by white-nose syndrome since its first appearance in 2006.

6. Most bats have only one pup each year.

7. In Delaware, you can volunteer to monitor bat populations, which could mean driving around rural areas and listening for their unique, squeaky calls. To volunteer, call (302) 735-3600 or go to www.dnrec.delaware.gov/fw/bats.